High Resolution Low Voltage Scanning Electron Microscopy: Reduced Radiation Damage on Cryo-specimens

In comparison with the developers of other forms of instrumentation, scanning electron microscope manufacturers are among the most conservative of people. New concepts usually must wait many years before being exploited commercially. The field emission gun, developed by Albert Crewe and his coworkers in 1968 is only now becoming widely available in commercial instruments, while the innovative lens designs of Mulvey are still waiting to be commercially exploited. The associated electronics is still in general based on operating procedures which have changed little since the original microscopes of Oatley and his co-workers.The current interest in low-voltage scanning electron microscopy will, if sub-nanometer resolution is to be obtained in a useable instrument, lead to fundamental changes in the design of the electron optics. Perhaps this is an opportune time to consider other fundamental changes in scanning electron microscopy instrumentation.

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Imaging of polymer single crystals in low-voltage, high-resolution scanning electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178665 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1106-1107

Author(s):

W.W. Adams ◽

G. Price ◽

A. Krause

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

High Resolution ◽

Single Crystals ◽

Low Voltage ◽

Polymer Surface ◽

Beam Current ◽

Image Features ◽

First Results ◽

Scanning Electron

It has been shown that there are numerous advantages in imaging both coated and uncoated polymers in scanning electron microscopy (SEM) at low voltages (LV) from 0.5 to 2.0 keV compared to imaging at conventional voltages of 10 to 20 keV. The disadvantages of LVSEM of degraded resolution and decreased beam current have been overcome with the new generation of field emission gun SEMs. In imaging metal coated polymers in LVSEM beam damage is reduced, contrast is improved, and charging from irregularly shaped features (which may be unevenly coated) is reduced or eliminated. Imaging uncoated polymers in LVSEM allows direct observation of the surface with little or no charging and with no alterations of surface features from the metal coating process required for higher voltage imaging. This is particularly important for high resolution (HR) studies of polymers where it is desired to image features 1 to 10 nm in size. Metal sputter coating techniques produce a 10 - 20 nm film that has its own texture which can obscure topographical features of the original polymer surface. In examining thin, uncoated insulating samples on a conducting substrate at low voltages the effect of sample-beam interactions on image formation and resolution will differ significantly from the effect at higher accelerating voltages. We discuss here sample-beam interactions in single crystals on conducting substrates at low voltages and also present the first results on HRSEM of single crystal morphologies which show some of these effects.

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Visualizing the surface morphology of non-fullerene acceptor blends by automated segmentation of spatially resolved electron spectra from ultra-low voltage scanning electron microscopy

10.29363/nanoge.hopv.2019.107 ◽

2019 ◽

Author(s):

Martin Pfannmöller ◽

Jochen Kammerer ◽

Rasmus Schröder ◽

Irene Wacker ◽

Riva Alkarsifi ◽

...

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Surface Morphology ◽

Low Voltage ◽

Automated Segmentation ◽

Electron Spectra ◽

Spatially Resolved ◽

Voltage Scanning ◽

Scanning Electron

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Low Voltage Scanning Electron Microscopy

Microscopy Today ◽

10.1017/s1551929500057813 ◽

2002 ◽

Vol 10 (2) ◽

pp. 22-23 ◽

Cited By ~ 2

Author(s):

David C Joy ◽

Dale E Newbury

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

High Spatial Resolution ◽

Low Voltage ◽

Incident Beam ◽

Operational Mode ◽

X Ray ◽

Rapid Fall ◽

Voltage Scanning ◽

Scanning Electron

Low Voltage Scanning Electron Microscopy (LVSEM), defined as operation in the energy range below 5 keV, has become perhaps the most important single operational mode of the SEM. This is because the LVSEM offers advantages in the imaging of surfaces, in the observation of poorly conducting and insulating materials, and for high spatial resolution X-ray microanalysis. These benefits all occur because a reduction in the energy Eo of the incident beam leads to a rapid fall in the range R of the electrons since R ∼k.E01.66. The reduction in the penetration of the beam has important consequences.

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